Mesoamerica is one of the few areas in the world where archaic state societies emerged. In this vast territory that includes more than half of Mexico, as well as Guatemala, Belize and parts of Honduras and El Salvador, different types of states coexisted in the so-called Classic Period (100–900 ce). This chapter will deal with one of the major regions where large multiethnic states and cities developed, a volcanic and seismic region characterised by a lacustrine environment and a diversity of resources (obsidian to the northeast, aquatic animals and plants, forest resources, agricultural land, volcanic rocks, etc.).
As Sanders, Parsons and Santley (1979: 1–2) put it, the Basin of Mexico played a significant role in the development of Mesoamerican civilisation:
At the time of the Spanish Conquest, it had the densest population, the largest and most highly differentiated urban centers, and the most complex political and economic organization in the history of Mesoamerican civilization.
An important effort to understand the Basin of Mexico was a long-term project during the 1950s through 1970s, headed by José Luis Lorenzo, at the former Department of Prehistory (of the Instituto Nacional de Antropología e Historia, Mexico), aimed at understanding the geological, glaciological, geomorphological, palaeoenvironmental and early occupational history of the basin (Lorenzo & Mirambell 1986; Lorenzo 1969; Mooser, Lorenzo & White 1956).